export default {
  Base64:function() {
    let  _keyStr ='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='

    // public method for encoding
    this.encode = function(input) {
      var output = ''
      var chr1, chr2, chr3, enc1, enc2, enc3, enc4
      var i = 0
      input = this._utf8_encode(input)
      while (i < input.length) {
        chr1 = input.charCodeAt(i++)
        chr2 = input.charCodeAt(i++)
        chr3 = input.charCodeAt(i++)
        enc1 = chr1 >> 2
        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4)
        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6)
        enc4 = chr3 & 63
        if (isNaN(chr2)) {
          enc3 = enc4 = 64
        } else if (isNaN(chr3)) {
          enc4 = 64
        }
        output =
          output +
          _keyStr.charAt(enc1) +
          _keyStr.charAt(enc2) +
          _keyStr.charAt(enc3) +
          _keyStr.charAt(enc4)
      }
      return output
    }

    // public method for decoding
    this.decode = function(input) {
      var output = ''
      var chr1, chr2, chr3
      var enc1, enc2, enc3, enc4
      var i = 0
      input = input.replace(/[^A-Za-z0-9\+\/\=]/g, '')
      while (i < input.length) {
        enc1 = _keyStr.indexOf(input.charAt(i++))
        enc2 = _keyStr.indexOf(input.charAt(i++))
        enc3 = _keyStr.indexOf(input.charAt(i++))
        enc4 = _keyStr.indexOf(input.charAt(i++))
        chr1 = (enc1 << 2) | (enc2 >> 4)
        chr2 = ((enc2 & 15) << 4) | (enc3 >> 2)
        chr3 = ((enc3 & 3) << 6) | enc4
        output = output + String.fromCharCode(chr1)
        if (enc3 != 64) {
          output = output + String.fromCharCode(chr2)
        }
        if (enc4 != 64) {
          output = output + String.fromCharCode(chr3)
        }
      }
      output = this._utf8_decode(output)
      return output
    }

    // private method for UTF-8 encoding
    this._utf8_encode = function(string) {
      string = string.replace(/\r\n/g, '\n')
      var utftext = ''
      for (var n = 0; n < string.length; n++) {
        var c = string.charCodeAt(n)
        if (c < 128) {
          utftext += String.fromCharCode(c)
        } else if (c > 127 && c < 2048) {
          utftext += String.fromCharCode((c >> 6) | 192)
          utftext += String.fromCharCode((c & 63) | 128)
        } else {
          utftext += String.fromCharCode((c >> 12) | 224)
          utftext += String.fromCharCode(((c >> 6) & 63) | 128)
          utftext += String.fromCharCode((c & 63) | 128)
        }
      }
      return utftext
    }

    // private method for UTF-8 decoding
    this._utf8_decode = function(utftext) {
      var string = ''
      var i = 0
      var c,c1,c2,c3
      c = c1 = c2 = 0
      while (i < utftext.length) {
        c = utftext.charCodeAt(i)
        if (c < 128) {
          string += String.fromCharCode(c)
          i++
        } else if (c > 191 && c < 224) {
          c2 = utftext.charCodeAt(i + 1)
          string += String.fromCharCode(((c & 31) << 6) | (c2 & 63))
          i += 2
        } else {
          c2 = utftext.charCodeAt(i + 1)
          c3 = utftext.charCodeAt(i + 2)
          string += String.fromCharCode(
            ((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63)
          )
          i += 3
        }
      }
      return string
    }
  }
}
